Exam 2: Kinematics: Motion in One Dimension

A race car circles 10 times around a circular 8.0-km track in 20 min.Using SI units (a)what is its average speed for the ten laps? (b)what is its average velocity for the ten laps?

A racquetball strikes a wall with a speed of 30 m/s and rebounds in the opposite direction with a speed of 26 m/s.The collision takes 20 ms.What is the average acceleration of the ball during the collision with the wall?

A bat,flying toward the east at 2.0 m/s,emits a shriek that is reflected back to it from a wall that is 20.0 m in front of the bat at the instant the shriek is emitted.Sound travels at 340 m/s in the air.How many milliseconds after emitting the shriek does the bat hear the reflected echo from the wall?

A runner ran the marathon (approximately 42.0 km)in 2 hours and 57 min.What was the average speed of the runner in m/s?

Two objects are thrown from the top of a tall building.One is thrown up,and the other is thrown down,both with the same initial speed.What are their speeds when they hit the street? Neglect air.

A stone is thrown with an initial upward velocity of 7.0 m/s.If we take upward as the positive direction,what is the velocity of the stone after 0.50 s,assuming there is no air?

The graph in the figure shows the velocity of a particle as it travels along the x-axis.(a)In what direction (+x or -x)is the acceleration at t = 0.5 s? (b)In what direction (+x or -x)is the acceleration at t = 3.0 s? (c)What is the average acceleration of the particle between t = 2.0 s and t = 4.0 s? (d)At what value of t is the instantaneous acceleration equal to 0 m/s²?

The graph in the figure shows the position of a particle as it travels along the x-axis.What is the magnitude of the instantaneous velocity of the particle when t = 1.0 s?

Consider a car that travels between points A and B.The car's average speed can be greater than the magnitude of its average velocity,but the magnitude of its average velocity can never be greater than its average speed.

Human reaction time is usually greater than 0.10 s.If your friend holds a ruler between your fingers and releases it without warning,how far can you expect the ruler to fall before you catch it,assuming that air has no effect on the ruler?

A child standing on a bridge throws a rock straight down.The rock leaves the child's hand at time t = 0 s.If we take upward as the positive direction,which of the graphs shown below best represents the velocity of the stone as a function of time?

A rock is projected upward from the surface of the Moon,at time t = 0 s,with an upward velocity of 30.0 m/s.The acceleration due to gravity at the surface of the Moon is 1.62 m/s²,and the Moon has no atmosphere.The height of the rock when it is descending with a speed of 20.0 m/s is closest to

An object is moving with constant non-zero velocity in the +x direction.The position versus time graph of this object is

The figure shows a graph of the position x of two cars,C and D,as a function of time t. According to this graph,which statements about these cars must be true? (There could be more than one correct choice.)

An object is thrown upwards with a speed of 13 m/s.How long does it take to reach a height of 4.0 m above the projection point while descending? Neglect air resistance.

At the instant a traffic light turns green,a car that has been waiting at the intersection starts ahead with a constant acceleration of 2.00 m/s².At that moment a truck traveling with a constant velocity of 15.0 m/s overtakes and passes the car. (a)Calculate the time necessary for the car to reach the truck. (b)Calculate the distance beyond the traffic light that the car will pass the truck. (c)Determine the speed of the car when it passes the truck.

A car is traveling at 26.0 m/s when the driver suddenly applies the brakes,causing the car to slow down with constant acceleration.The car comes to a stop in a distance of 120 m.How fast was the car moving when it was 60.0 m past the point where the brakes were applied?

The captain orders his starship to accelerate from rest at a rate of "1 g" (1 g = 9.8 m/s²).How many days does it take the starship to reach 10% the speed of light? (Light travels at 3.0 × 10⁸ m/s.)

An airplane increases its speed at the average rate of 15 m/s².How much time does it take to increase its speed from 100 m/s to 160 m/s?

If,in the figure,you start from the Bakery,travel to the Cafe,and then to the Art Gallery in 2.00 hours,what is your (a)average speed? (b)average velocity?